North America Distribution

Facts

The leaves of prairie willow have white and reddish hairs on the top surface (giving them a gray-green appearance) and white hairs on the undersurface. These hairs may help protect leaves from desiccation and solar heat, making this species more tolerant of drought than other willows. Short-tongued bees and flies visit the silky flowers for nectar. Caterpillars of many moths and butterflies, including the Striped Hairstreak (Satyrium liparops) eat the foliage. Many willows (Salix species) have bitter-tasting bark that contains derivatives of salicylic acid, the main compound in aspirin.

Family

Genus

Information from Dichotomous Key of Flora Novae Angliae

15. Salix humilis
Marsh.
N

prairie willow.
Salix conifera Muhl.;
S. humilis Marsh. var.
angustifolia (Barratt) Anderss.;
S. muehlenbergiana Willd. var.
angustifolia Barratt;
S. tristis Ait. var.
glabrata (Anderss.) Anderss.
•
CT, MA, ME,
NH,
RI,
VT; nearly throughout. Fields, roadsides, forest borders, sand plains, woodlands, often in well-drained soils.
Salix humilis can be confused with
S. cinerea ssp.
oleifolia, especially when the ridges on decorticated branches are longer than usual (as does occasionally occur on New England material). The two taxa can be separated on the basis of plant height, leaf blade outline, stipules, anther color, and ovary pubescence.
Salix humilis is 0.3–3 m tall, with leaf blades 2.3–7.5 times as long as wide, lacking or with rudimentary stipules on the first leaves (i.e., those that expand from the winter bud), has purple anthers that turn yellow in age, and has wavy or crimped hairs on the ovary.
Salix cinerea ssp.
oleifolia is 2–12 m tall, with leaf blades 1.8–4.3 times as long as wide, with foliaceous stipules on the first leaves, has yellow anthers, and ± straight hairs on the ovary.